What was the planned first phase of Operation Downfall, targeting southern Kyūshū, called?

The planned first phase of Operation Downfall, targeting southern Kyūshū, was called Operation Olympic.

Olympic was scheduled to begin on November 1, 1945. Its objective was to seize the southern third of Kyūshū, Japan’s southernmost main island, and establish airfields and staging areas for the next phase of the invasion.

The second phase, Operation Coronet, was planned for spring 1946 and would have attacked the Kantō Plain near Tokyo on Honshū. Together, Olympic and Coronet made up Operation Downfall, the proposed Allied invasion of Japan.

Olympic was canceled before it began because Japan surrendered in August 1945. The plan included a very large naval force and extensive air support. Its intended landing beaches and military preparations later became important evidence of how dangerous a home-island invasion might have been.